Some Salt with Those Fireworks?

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Some Salt with Those Fireworks?

Tonight people across the U.S. will celebrate America’s Independence Day with one of the most magical kinds of shows: fireworks. These loud explosions of bright-colored streaks and stars can be seen for miles. But what are those streaks and stars made of? Most fireworks are cardboard tubes filled with pyrotechnic stars, which are made of salts, metals and other stuff that catches on fire and burns in different colors. To make hearts, Saturn rings and other shapes in the sky, you arrange the stars a certain way inside the tube, then bundle lots of tubes together. A firework is truly like a small bomb and is dangerous, so you never want to play with one yourself. But if you keep a good distance from them, you’ll get one sparkly, salty show.

Wee ones: Red, white and blue are great colors for today. Can you find 1 item of each color in your room? Which one is the longest?

Little kids: If your town fireworks show blasts off 3 Saturn-shaped bursts, where each Saturn has 1 globe and 1 ring, how many shapes is that in total? Bonus: Fireworks show up best in a dark sky. If the sun sets at 8:30 pm and the show starts 10 minutes later, at what time do the fireworks start?

Big kids: If they fire 5 fireworks each minute, how many fireworks do you see in a 20-minute show? (Don’t worry about an extra one at the very start.) Bonus: A “spider” firework (like in the photo) needs 160 trailing stars to make all those points, and a tube can hold 20 stars. How many total tubes does a spider need? Count up by 20s if it helps!

The sky’s the limit, for real: If the big finale uses 100 tubes in red, white and blue, and there are twice as many red tubes as white and twice as many blue tubes as white, how many tubes of each color does the finale use?

Answers:Wee ones: Items might includes socks, shirts and other clothing; Lego bricks; and other toys.

Little kids: 6 shapes. Bonus: At 8:40 pm.

Big kids: 100 fireworks. Bonus: 8 tubes.

The sky’s the limit: 20 white tubes, and 40 each of red and blue. There are 2 parts red, 2 parts blue and 1 part white, making 5 parts total. So dividing 100 by 5 will give you the amount for 1 part (white). Then there are twice as many red, and also twice as many blue.

About the Author

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking while still in diapers, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.